Atomic Structure

Question 1

Properties of a proton

Answer 1

mass - 1
charge - 1+
located in the nucleus of the atom

Question 2

properties of a neutron

Answer 2

mass - 1
charge - neutral
located in the nucleus of the atom

Question 3

properties of an electron

Answer 3

mass - negligible
charge - 1-
located in the energy shells/levels of an atom

Question 4

who had the first ideas about atoms

Answer 4

ancient Greeks

Question 5

John Dalton model

Answer 5

John Dalton published his ideas about atoms in 1803. He thought that all matter was made of tiny particles called atoms which he imagined as tiny spheres that could not be divided.

Question 6

J J Thompson model

Answer 6

100 years after Dalton, J J Thomson carried out experiments and discovered the electron. This led him to suggest the plum pudding model of the atom. In this model, the atom is a ball of positive charge with negative electrons embedded in it - like currants in a Christmas pudding.

Question 7

Ernest Rutherford experiment

Answer 7

In 1909 Ernest Rutherford designed an experiment to test the plum pudding model. In the experiment, positively charged alpha particles were fired at thin gold foil. Most alpha particles went straight through the foil. But a few were scattered in different directions.

Question 8

Ernest Rutherford model

Answer 8

The evidence he gathered in his experiment led Rutherford to suggest a new model for the atom, called the nuclear model. In this model, the mass of an atom is concentrated at its centre (the nucleus) and the nucleus is positively charged.

Question 9

How many max electrons can be in the inner shell?

Answer 9

2

Question 10

How many max electrons can be in the second shell

Answer 10

8

Question 11

How many max electrons can be in the third shell?

Answer 11

8

Question 12

What tells you how many electrons are in an atoms outer shell?

Answer 12

The group number

Question 13

What tells you how many shells an atom has?

Answer 13

The period it’s in (on the periodic table)

Question 14

How do you calculate relative atomic mass?

Answer 14

Ar = total mass of atoms/total number of atoms
or
Ar = (abundance × mass + abundance × mass)/total abundance

Question 15

How do you calculate relative formula mass?

Answer 15

• work out how many atoms of each element there are in the chemical formula
• add together the Ar values for all the atoms of each element present
• so Mr=the Ar of all of the atoms in the formula

Question 16

What is the relative formula mass of CO2?

Answer 16

It consists of one carbon atom (Ar = 12) and two oxygen atoms (Ar = 16):
Mr of CO2 = 12 + 16 + 16 = 44
It could also be calculated this way:
Mr of CO2 = (1 × 12) + (2 × 16) = 12 + 32 = 44

Question 17

The is a 75% abundance of Cl with an atomic mass of 35 and a 25% abundance of Cl with an atomic mass of 37
Find Cl’s atomic mass

Answer 17

Relative atomic mass = [(75/100) x 35] + [(25/100) x 37] = 35.5

Question 18

What is an isotope

Answer 18

Isotopes are atoms of the same element with different numbers of neutrons.They have the same number of protons.

Question 19

What is the difference in properties between isotopes of the same element?

Answer 19

Isotopes of the same element have different physical properties (e.g. density, radioactivity) but the same chemical properties (e.g. reactivity)